So my sheevaplug arrived with a broken console output. Everything else worked fine (I could see it boot and get an IP address from my router) and also channel A on the FTDI chip would connect fine to the JTAG debugger.

I did some investigation of the schematics and identified some possible locations where there may be an issue. I opened it up and found that the first 3 pins on the main CPU board's ribbon header connector going to the JTAG board were bridged at the back of the PCB where they were soldered. Some quick work with a soldering iron to resolder them everything was fixed. My console output (channel B) now works.

Anyone who has this same issue may want to consider disassembling their SheevaPlug to check this, although it may void your warranty so proceed at your own risk.

I did some investigation of the schematics and identified some possible locations where there may be an issue. I opened it up and found that the first 3 pins on the main CPU board's ribbon header connector going to the JTAG board were bridged at the back of the PCB where they were soldered. Some quick work with a soldering iron to resolder them everything was fixed. My console output (channel B) now works.